Electrically heated blanket



June 1l, 1940. l. o. MOBERG ELECTRICALLY HEATED BLANKE'I Filed March '7. 1959 I5 Sheets-Sheet .l

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3 Sheets-Sheet 2 I. O. MOBRG Filed March 7, 1939 ELECTRICALLY Al-IEATE'D BLANKET 'June 1940.

INVENTOR grp-49 *1'21'1 ATTORNEY June 1l, 1940. l. o. MoBERc-r. 2,203,918

ELECTRICALLY HEATED BLANKET Filed March 7, 1959 3 Sheets-Sheet 3 INVENTOR v M1/C97 W' y Patented June 11, 1940 um'ran s'mxrrasl PATENT OFFICE 2,203,918 ynLnc'nuuiLLr nEA'rED naamw Ivar 0. Moberg, Lowell, Mass., aslignor to Nashua Manufacturing Company, Bos

ton, Masha corporation of New Hampshire Application March 7, 1939, Serial No. 260,250

l2 Claims.

aims to improve both the construction and methy l ods of manufacture of such blankets with a view to producing a superior article at a reduced manufacturing expense.

As made heretofore, these blankets have involved a tremendous amount of sewing in connection with the placement and fastening of the conductors in their proper positions. This is a time consuming operation on an article as large as a bed blanket. Accordingly, the present invention is directed especially to eliminating the ings, and the novel features will be particularly pointed out in the appended claims.

In the drawings: g.

Figure l is a plan view of a blanket at an intermedite stage in the process of manufacture; g Fig. 2 is an edge view of the blanket shown in Fig. l; l

Fig. 3 is a plan view showing the blanket at the time the electrical conductors or wires are threaded into it; Fig. 4 is a perspective view of the nished blanketand Fig. 5 is a fragmentary, sectional view approximately on.the line 5 5, Fig. l.

Referring first to/Figs. l and 2, the article there shown comprises a double blanket fabric woven in the form there illustrated. It consists oi end sections 2 and 3 and an intermediate body section, all woven in an integral structure. The two plies may be separate except for being interwoven at certain points in accordance with the invention, and they may be of the same or of diil'erent weights; weaves, or constructions. Acgocordingto. the. preferred method of procedure, and assuming that the weaving operation begins at the lower edge of the blanket shown in Fig. 1, a tubular fabric is woven until the desired length for the section 2 has been completed. This part is designed to form the foot portion of the blanket,

necessity for most of the sewing, providing a.

and is made of suitable length to provide the desired length for tucking in. When this section has been completed a change in the weave is introduced and continues throughout the manufacture of the fbody section. No change in the 5 warp or filling yarns is'required, but the harness motion is made such that the threads are differently manipulated, with the result that the two plies are interwoven along their opposite margins 4--0 into a-solid two-ply fabric. In 10 weaving the portion between these margins certain of the warp threads are made to act as binders to interweave the two plies together at spaced intervals, as indicated at 5. Either binder warps alone, or in combination with filling threads, 15

v may be used to interweave the two plies at these points and thusto tie them together along the lines 5 throughout the entire length ofthe body portion of the blanket. These lines of interweaving are so spaced as to provide ducts or -conduits 20 i of suitable dimensions and of appropriate number to receive the entire set of electric'conductors. When this portion of the blanket has been woven, the harness motion is again changed to produce 'a tubular weave for making the sec- 25 tion 3, this part of the fabric being like the section 2. The Weaving operations above described are then repeated to produce other blankets of the same construction, these operations being automatically controlled by mecha- 30 nisms with which blanket manufacturers are entirely familiar. y

A later operation consists in threading the electric conductors through the ducts 6 in the `body portion of the blanket. 'I'his is convenient- 35 ly accomplished in the manner shown in Fig. 3, bearing in mind the fact that the opposite ends oi the ducts open into the tubular 'woven sections 2 and 1 in which the plies are completely separate except at the selvage edges. It will be seen l40 that if these sections 2 and 3 are turned backwardly over the body portion ofthe blanket, as shown in said ligure, the ends of thel ducts then will be exposed. Two persons working together at opposite ends of the blanket can therefore 45 n' readily thread the conductors through the ducts with a suitable guiding implement to which one end of the conductor is fastened. A typical arrangement of the conductors 1 is shown in Fig. 3. Usually they are arranged in two groups so that they may be connected at an external controller in a series or parallel relationship, as desired. It is customary, also, to vary the spacing, .approximately as indicated in Fig. 3, the wires 'being located more closely together in the'cen- '55 trai portion of the blanket than toward its opposite edges.

Before the wires have been installed, one or both plies of the fabric are napped. Assuming that both are of the same weight and construction, it is preferable to weave each with a face and a back. In other words, the weft or filling threads, which are much larger than the warp threads and are relied upon to furnish the material from which the nap is produced, are located chiefly at one side of the warp threads, thus exposing a larger area of the filling to the napping operation. This face in each ply is outermost, and such an arrangement lends itself readily to the Weaving or" a blanket in the manner above described since, in the tubular portions, the fill-y ing threads extend continuously through the selvage from one ply into the next. In such an arrangement either side of the blanket can be regarded as the top or the bottom, but in some cases it is preferable to make the two plies of quite different weights, the lower ply being lighter and citen un-napped so that the heat from the conductors may penetrate it more readily, while the upper ply is heavier and is napped, thus giving it better heat insulating properties.

After the foregoing operations have been completed, the blanket may be finished by the usual methods. It is customary to enclose both the top and bottom edges in an attractive binding fabric, -such as that shown at 8 in Fig. 4, this fabric extending over and around both edges of the tubular fabric and the two being secured together by the stitches which fasten the binding in place. As a rule the wires 1 are anchored to a tape or section of strong cloth positioned between the plies and stitched to them, and the ends are either connected internally to a cable which is led through a slot B, Fig. 4, in one edge of the blanket, or else the wires 1 themselves are led through this slot. Various other arrangements of the conductors may be employed with this construction. For example, an alternative arrangement consists in running a conductor through one of the ducts, then doubling it back upon itself and running it again through the.

same slot, so that two lengths of the conductor are housed in each duct. The loops so made in the wires at one end of the blanket may be anchored by means of a tape extending through them and stitched to the blanket. At the opposite end the wires are held against pulling back by the interwoven partitions separating adjacent ducts.

From the foregoing it will be appreciated that the invention provides an electrically heated blanket which can be manufactured far more economically than prior commercial constructions, at least those of which I have been able to learn. The entire fundamental, structure of the blanket can be produced in automatic looms of well known forms capable of high production and adapted to make fabrics of excellent quality. As above pointed out, the construction is such that the operation of threading in the wires is facilitated and the finishing operations are essentially like those performed on any blanket of a corresponding quality.

While I have herein shown and described a typical embodiment of my invention, it will be understood that the invention is not limited to the precise details described or to the exact procedure set forth.

Having thus described my invention, what I desiretoclaimasnewis:

1. A blanket of the character described com prising a double blanket fabric including a main body section occupying the greater portion of the area of the blanket, the two plies of fabric in said section being interwoven at spaced intervals to provide a series of parallel ducts between the plies, said ducts being adapted to receive electric conductors, the blanket also including marginal portions in which the plies are separate from each other.

2. A blanket oi' the character described comprising a double blanket fabric including a main body section occupying the greater portion of the area of the blanket, the two plies of fabric in said section being interwoven at spaced intervals to provide a series of parallel ducts between the plies, said ducts being adapted to receive electric conductors, the blanket also including a marginal portion in which the plies are separate from each other and into which the ends of said ducts open.

3. A blanket according to preceding claim 2, in which the plies are interwoven into a two-ply fabric at the opposite edges of said main section, the portions so interwoven extending parallel to the ducts.

4. A blanket of the character described comprising a double blanket fabric including a main body section occupying the greater portion of the area of the blanket, the two plies of fabric in said section being interwoven by spaced binder warps to provide a series of narrow parallel ducts between the plies adapted for the threading therethrough of electric conductors, saidrducts extending lengthwise of the blanket, the blanket also including a relatively short marginal portion at the upper end of the blanket and a longer marginal portion at the lower end thereof in which the plies are separated and into which the ends of theducts open, the edges of said plies at both ends of the blanket being bound together.

5. A blanket according to preceding claim 4, which includes marginal portions at the opposite longitudinal edges of the blanket in which the plies are woven together into an integral two-ply structure.

6. A blanket according to preceding claim 4, which includes marginal portions at the opposite longitudinal edges of the blanket in which the plies are woven together into an integral twoply structure, the filling threads extending transversely of the fabric and the same filling threads being included in both plies.

7. A blanket of the character described com` prising a double blanket fabric including a main body section occupying the greater portion of the area of the blanket, the two plies of fabric in said section being interwoven by spaced binder warps to provide a series of narrow parallel ducts between the plies adaptedl for the threading therethrough of electric conductors, said ducts extending lengthwise of the blanket, the blanket also including a marginal portion at one end thereof woven in a tubular form, the ducts openinginto said tubular portion and the end edges of said tubular portion being bound together throughout at least the greater part of their length.

8. A blanket according vto preceding claim 1, in which the top ply consists of a heavy blanket fabric with its upper surface napped.

9. A blanket according to preceding claim 1, in which both of said plies are woven with their face and of different constructions. 7S

the face of the uppermost ply being up and that of the lowermost ply being down, and the faces of both plies beingnap'ped.

10. A blanket of the character described comprising a double blanket fabric including a .main body section occupying the greater portion of the area of the blanket, the two plies of fabric in said section being interwoven at spaced intervals to provide a series of parallel ducts between the plies, said ducts being adapted to receive electric conductors, said blanket including marginal portions at the head and foot thereof in which the plies are -separated from each other and into which the ends of said ducts open, the blanket also having additional margins of substantial widthat the opposite lateraledges of said body section and extending parallel to said ducts in which the two plies are interwoven with each other into a solid fabric. t

11. A blanket according to preceding claim l0, in which said ductsare more closely spaced in the central portion of the blanket between opposite lateral edges than in theparts thereof at opposite sides of said centralportiom 12. A blanket of the character described comprising a double'blanket fabric including a main body section occupying the greater portion of the area of the blanket, the two plies of fabric in said section being interwoven at spaced intervals to provide a series af parallel ducts between the plies, said blanket also including portions at the opposite ends of said main body section in which f the plies are separate from yeach other and into the plies are interwoven with each other into a 20 solid fabric.

IVAR O. MOBERG. 

